When you are building your bike each layer is a like a specific group of things that serve a distinc
When you are building your bike each layer is a like a specific group of things that serve a distinct purpose (grouping things into a function), so a layer could be the engine or custom seats. All the layers stack up and you have your bike. Building from layering allows you to build (and easily modify) your bike. Swapping the engine would be as simple as replacing or modifying the engine layer. This modular system gives you flexibility to create what you need while making it easy to modify without complexity.
